antos-frontend/src/core/db.ts
2020-06-17 21:06:55 +02:00

203 lines
7.4 KiB
TypeScript

// Copyright 2017-2018 Xuan Sang LE <xsang.le AT gmail DOT com>
// AnTOS Web desktop is is licensed under the GNU General Public
// License v3.0, see the LICENCE file for more information
// This program is free software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see https://www.gnu.org/licenses/.
namespace OS {
export namespace API {
/**
* Simple Virtual Database (VDB) application API.
*
* This API abstracts and provides a standard way to
* connect to a server-side relational database (e.g. sqlite).
*
* Each user when connected has their own database previously
* created. All VDB operations related to that user will be
* performed on this database.
*
* The creation of user database need to be managed by the server-side API.
* The VDB API assumes that the database already exist. All operations
* is performed in tables level
*
* @export
* @class DB
*/
export class DB {
/**
* A table name on the user's database
*
* @private
* @type {string}
* @memberof DB
*/
private table: string;
/**
*Creates an instance of DB.
* @param {string} table table name
* @memberof DB
*/
constructor(table: string) {
this.table = table;
}
/**
* Save data to the current table. The input
* data must conform to the table record format.
*
* On the server side, if the table doest not
* exist yet, it should be created automatically
* by inferring the data structure of the input
* object
*
* @param {GenericObject<any>} d data object represents a current table record
* @returns {Promise<API.RequestResult>}
* @memberof DB
*/
save(d: GenericObject<any>): Promise<API.RequestResult> {
return new Promise(async (resolve, reject) => {
try {
const r = await API.handle.dbquery("save", {
table: this.table,
data: d,
});
if (r.error) {
return reject(API.throwe(r.error.toString()));
}
return resolve(r);
} catch (e) {
return reject(__e(e));
}
});
}
/**
* delete record(s) from the current table by
* a conditional object
*
* @param {*} c conditional object, c can be:
*
* * a `number`: the operation will delete the record with `id = c`
* * a `string`: The SQL string condition that selects record to delete
* * a conditional object represents a SQL condition statement as an object,
* example: `pid = 10 AND cid = 2` is represented by:
*
* ```typescript
* {
* exp: {
* "and": {
* pid: 10,
* cid: 2
* }
* }
* ```
*
* @returns {Promise<API.RequestResult>}
* @memberof DB
*/
delete(
c: GenericObject<any> | number | string
): Promise<API.RequestResult> {
return new Promise(async (resolve, reject) => {
const rq: any = { table: this.table };
if (!c || c === "") {
reject(API.throwe("OS.DB: unknown condition"));
}
if (isNaN(c as number)) {
rq.cond = c;
} else {
rq.id = c;
}
try {
const r = await API.handle.dbquery("delete", rq);
if (r.error) {
return reject(API.throwe(r.error.toString()));
}
return resolve(r);
} catch (e) {
return reject(__e(e));
}
});
}
/**
* Get a record in the table by its primary key
*
* @param {number} id the primary key value
* @returns {Promise<GenericObject<any>>} Promise on returned record data
* @memberof DB
*/
get(id: number): Promise<GenericObject<any>> {
return new Promise(async (resolve, reject) => {
try {
const r = await API.handle.dbquery("get", {
table: this.table,
id: id,
});
if (r.error) {
return reject(API.throwe(r.error.toString()));
}
return resolve(r.result as GenericObject<any>);
} catch (e) {
return reject(__e(e));
}
});
}
/**
* Find records by a condition
*
* @param {GenericObject<any>} cond conditional object
*
* a conditional object represents a SQL condition statement as an object,
* example: `pid = 10 AND cid = 2 ORDER BY date DESC` is represented by:
*
* ```typescript
* {
* exp: {
* "and": {
* pid: 10,
* cid: 2
* }
* },
* order: {
* date: "DESC"
* }
* }
* ```
* @returns {Promise<GenericObject<any>[]>}
* @memberof DB
*/
find(cond: GenericObject<any>): Promise<GenericObject<any>[]> {
return new Promise(async (resolve, reject) => {
try {
const r = await API.handle.dbquery("select", {
table: this.table,
cond,
});
if (r.error) {
return reject(API.throwe(r.error.toString()));
}
return resolve(r.result as GenericObject<any>[]);
} catch (e) {
return reject(__e(e));
}
});
}
}
}
}